Piston connection



March ".17, 1931.

R. EsNAuLT-PELTERIE 1,796,687

PISTON CONNECTION Filed Jan. 16, 1929 Patented Mar. 17, 1931 UNITEDSTATES ROBERT ESNAULT-PELTERIE, F PARIS, FRANCE PISTON CONNECTION Application med January 16, 1929, Serial No. 333,004, and in Great Britain January 19, `1928.

lThisinvention relates `to pistons for hydraulic power transmission apparatus and/or pumps and more particularly to pistons and piston actuating means for use in such l apparatus, and the invention has for its object to provide an improved construction of piston and actuating means therefor with a view of avoiding lateral friction and occasionally even rupture of the parts by transverse stresses incidental thereto during the working of the apparatus. l

According to the present invention the piston and an actuating or piston rod therefor are loosely associated together by means of a-tubular extension of the piston surroundfing the actuating rod, contact between the actuating rod and thepston being obtained by a spring having a point of support on a member adapted to be reciprocated. In the preferred construction the actuating rod is provided with apointed end adapted to bear against a recess in the piston of a slightly greater angle of eonicity than the pointed rod end the piston being rovided with an integral or rigidlyattac ed sleeve which sur- `rounds the actuating rod between which and the saidsleeve a certain `amount of play or "clearance is rovided.

\ In order t at the invention may be clearly understood and readily carried into eifect, reference is made to the accompanying drawing which showsdiagrammatically and by way of example a construction 1n accordance with the present invention.

a5 l Figurel is a longitudinal section of part of an apparatus in accordance With the presont invention. i

Figure 2 drawn to an enlarged scale is a detail view of the piston actuating rod end and the adjacent partof the piston.

Referring to the drawing which shows -in section part of `a hydraulic power transmis- ;sion apparatus or pump, 1 is an outer tubular fiding member, which is integral with a lgildllow cylindricalreduced part 2. A fluid or 'semi-fluid medium 3 to be compressed is disposed in the bore 4 of the cylindrical part 2, the latter carrying two centering rings 5, 6 which `surround a piston 7 having a sleeveo extension 8, the latter surrounding a rod 9 between which and the sleeve 8 a sli ht amount of play or clearance is allowed. he rod 9 is pointed or of conical form at its outer end as at 10, see more particularly Figure 2, which end co-operates with a `surface 11 of a slightly greater angle of conicity than the pointed end of the rod 9. At its rear end the sleeve is flared orflanged as at 12 and the aforesaid rod is provided with a collar 13 which abuts against the inner end surface 14 of a cross-head 15, the end 16 of the rod 9 being rigidly secured in the crosshead 15 by means of a nut 17 and screwthread on the end 16 of the rod. Suitably interconnected with the cross-head 15 is a block 18 in which is a recess 19 to receive the dared or iianged end 12 of the sleeve extension 8 of the piston 7. It will be seen that a certain amount of play or clearance is allowed between the collar 13 and the flared or flanged end 12 of the extension sleeve 8. The cross-head 15 may be fitted with a pivot pin 2O receiving the end of a connecting rod 24 so that any displacement of the latter is communicated to the rod 9 which displaces the piston 7 the movement of which produces a pressure `in the power transmitting medium 3 in the bore 4 of the cylinder 2. 27 is packing interposed between the two centering rings 5 and 6, and 22 is a vent hole.

It will be readily understood thatduring the outer stroke of the cross-head 15 and when the pressure of the medium 3 decreases the piston 7 may have `a tendency to be retained by the friction of the packing 27 or rings 5-6 so that it would abandon contact with rod 9. Such `a device would then be improper for a suction pump. To avoid that difficulty a helical spring 23` is disposed around the sleeve extension 8 of the piston 90 7wvith sufficient play to permitof its lateral freedom. At one end such spring 23 presses on the flange 12 of the sleeve extension 8 and at the other one it fesses against an abutment provided in the block 95 18 secured to the cross-head 15, so that it always compels the sleeve extension `8 and piston 7 to follow the return movement of the cross-head 15, whether the medium 3 be under pressure or not.

It Will be understood from the foregoing description read in conjunction with the drawing that the rod 9 is free to oscillate in all directions by reason of the point contact of the pointed end l with the recess l1 and also because of the clearance or play between the rod 9, the sleeve extension 8, the flanged or viiared end and the collar 13. The piston 7 can thus remain exactly centered in the centering rings 5, 6 which are" disposed one on each side of the packing 27l so that the packing joint cannot be torn or ruptured by transverse displacements which may occur Y-in apparatusheretofore in use.. Y It should mbe'y *clearly 'understood' however that the movement of thecrosshead l and block 18 as a rigid whole may be effected in any suitable manner.

Furthermore, theinvention is n ot limited to the use of an actuating rod having a conical or pointed end, inasmuch .as any form of bearing between the said rod and piston which will -permit of articulation therebetween wll relieve vthe piston of lateral forces that would .otherwise -be imparted theretothrough the actuating'rod. l u

Whileonly a, single embodiment of the inventionlhas been hereinbefore described i and the pistontendng to hold thelatterin contact with said compression-sustaining ele'- ment. Y j 2. Fluid pressure apparatus, including a piston, albore withinwhich said piston reciprocatesa guided cross-head sliding substantially in alignment with said bore, a rod interposed between said piston and said crosshead, said'rod Vbeing mechanically connected to saidcross-head and adapted to abut against a surface of the piston, a member connected to said piston and extending therefrom along said rod but separated fromsuch rod, and av spring interposed between said member and the cross-head, said spring exerting a force through said member vtending to hold the lrod in contact with the piston. .f

3. Fluid pressure apparatus including -a reciprocatable piston, aguided cross-head, a rod interposed therebetween, said rod abutting againstisaidpiston in such manner as to permit relative angular displacement of their axes, a tension member external to said rod and secured to said piston, a spring surrounding said member, a seat on said member engaged by one end of said spring, and an abutment for said spring carried by the said crosshead at a point between the piston and the said seat, the stress of such spring tending to move the, piston and cross-head toward each other lso as to hold the rsaidl rod injyield ing contact with the piston.

4. The apparatus according to yclaim 3,l further characterized in that the `said member secured to the piston consists ofra tubular element loosely surrounding the said rod.

y The apparatus according Vto. A claim 3, further characterized in that the said member secured to the piston consists of a tubular element surrounding the said rod and rav dially separated therefromavsuliicient disf tance to permit small angular displacement thereof relative to the piston upon which said tubular element is mounted. v .,l

6. The apparatus according, toclaim y3, further,characterized in that the saidmem. ber secured to the piston ,consists of -a-tubular element loosely surrounding the said rod, one end of said element being rigidly secured to the piston and the othery end being outwardly flanged to provide a seat for the said spring.

7.- The apparatus. according to claim 3, further characterized in that the said crosshead-.is recessed to receive the freerend of the tension member, said member comprising a tubular element havingvan outwardly-projecting iiange, the recess opening `in 'said cross-head being restrictedto afford an abutment for one endof the said spring, the other end of the spring bearing against the flange of said tubular element. Y

8; kFluid pressure `apparatus including'ka reciprocatable piston, a two-part cross-head, a rod connectedatone en d to one part ofthe cross-head, the other endfof the rod-abutting against a surface ofthe piston'in such manner asto permit articulationtherebetween, a: tubular member -looselyembracing saidrod and at one end rigidly connected with said piston, the opposite end'of said member extending within the second Apart of saidcrosshead and Haring therewithin, anda helical compression. springsurrounding said inember and interposed between the flared portion thereof and thevcross-head partwithin which the member extends, whereby the 'force of the spring will be transmitted through the member toyieldingly hold the end'of the saidrod against the cross-head.

9. In a fluid pressure apparatus, the combination of a reciprocatable piston, a guided n cross-head, a compression-sustaining element interposed therebetween, said .element being operatively connected with said piston in such .manner las to permit articulationetherebetween, and a member'rigidly connected `with said piston and loosely vembracing,said pressure-sustaining element, the said member extending from the piston along the said compression-sustaininv element a distance equal to at least one-half the length of said element between the piston and the cross-head.

1n testimony whereof I have hereunto signed my name.

ROBERT ESNAULT-PELTERIE. 

